HP 39gs Master Manual page 333

Special characters
As in the view, special characters such as inequalities are
HOME
available from the
CHARS
view is somewhat different as can be seen right. There are no
CHARS
page up/down buttons, which makes it more difficult to move through.
The initial two rows are invalid characters that can't be used – exactly
why they were included is not clear.
Pressing will echo the single character under the curser, closing the
immediately to the CAS editing view. Pressing
continue selecting more. You can then either press
character you echo is inappropriate for the situation in the CAS view then it may be rejected.
Using the view is not the most convenient method and some commonly used characters are provided
CHARS
via special keyboard shortcuts.
These are:
SHIFT 0
SHIFT 1
SHIFT 3
SHIFT 5
SHIFT 6
SHIFT 8
SHIFT 9
view, although the appearance of the
∞
– inserts
– inserts i ( −1 )
π
– inserts
– inserts <
– inserts >
– inserts ≤
– inserts ≥
stores the character to a buffer and allows you to
to exit or use
ON
The button also has a special function in the CAS. If you
(-)
have entered a variable or constant, pressing
negative character before it even if the cursor is currently to
the right of the variable or constant. Pressing
change this to a + (positive) sign.
For example, pressing
This can be very useful when working with limits or integrals.
333
view and returning
CHARS
for the final character. If the
(-)
(-)
then will result in +
SHIFT 3 (-) (-)
will insert a
again will
∞
.